[Bug libgcc/125190] Stale documentation of __stack_chk_guard

[hjl.tools at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=125190

--- Comment #1 from H.J. Lu <hjl.tools at gmail dot com> ---
targhooks.cc has

/* Stack protection related decls living in libgcc.  */
static GTY(()) tree stack_chk_guard_decl;

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